Therma-Stor Ultra Aire XT105H, Owner'S Manual

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Ultra-Aire XT105H, XT155H, and XT205H Installer’s & Owner’s Manual
Compressor is not running. Dehumidification is being called
for. No fan call.
1. Defective compressor run capacitor (Sec. 7.6).
2. Loose connection in compressor circuit.
3. Defective compressor overload (Sec. 7.6A).
4. Defective compressor (Sec. 7.6).
5. Defrost thermostat open.
Compressor cycles on and off. Dehumidification is being called
for. No fan call
1. Low ambient temperature and/or humidity causing unit to
cycle through defrost mode.
2. Defective compressor overload (Sec. 7.6A).
3. Defective compressor (Sec. 7.6).
4. Defrost thermostat defective (Sec. 7.8).
5. Dirty air filter(s) or air flow restricted.
Fan is not running. Dehumidification or fan is being called for
1. Loose connection in fan circuit.
2. Obstruction prevents fan impeller rotation.
3. Defective fan.
4. Defective fan relay.
Low dehumidification capacity (evaporator is frosted
continuously). Dehumidification is being called for
1. Defrost thermostat loose or defective (Sec. 7.8).
2. Low refrigerant charge
3. Dirty air filter(s) or air flow restricted.
4. Excessively restrictive ducting connected to unit.
No ventilation. Ventilation is being called for.
1. Loose connection in ventilation control circuit
2. Loose connection in damper power circuit.
3. Defective fresh air damper.
Unit removes some water, but not as much as expected.
1. Air temperature and/or humidity have dropped.
2. Humidity meter and or thermometer used are out of
calibration.
3. Unit has entered defrost cycle (Sec. 5.8).
4. Air filter dirty (Sec. 4.1 & 4.2).
5. Defective defrost thermostat (Sec 5.8).
6. Low refrigerant charge (Sec. 5.4).
7. Air leak such as loose cover or ducting leaks.
8. Defective compressor (Sec. 5.6).
9. Restrictive ducting (Sec. 2.4).
10. Optional Condensate Pump Safety Switch open (Sec 5.11).
Unit Test to determine problem:
1. Detach field control wiring connections from main unit.
2. Connect the yellow and green pigtails from the main unit
together; only the impeller fan should run. Disconnect the
wires.
3. Connect the yellow and blue pigtails from the main unit
together; the compressor and impeller fan should run.
4. If these tests work, the main unit is working properly. You
should check the control panel and field control wiring for
problems next.
5. Remove the control panel from the mounting box and detach
it from the field installed control wiring. Connect the blue,
yellow, and green wires from the control panel directly to the
corresponding colored pigtails on the main unit. Leave the
violet, white and red wires disconnected!
6. Turn on the fan switch; the impeller fan should run. Turn off
the fan switch.
7. Turn on the humidity control; the compressor and impeller fan
should run.
8. If these tests work, the problem is most likely in the field
control wiring.
7.4 Refrigerant Charging
If the refrigerant charge is lost due to service or a leak, a new
charge must be accurately weighed in. If any of the old charge is
left in the system, it must be recovered before weighing in the new
charge. Refer to the unit nameplate for the correct charge weight
and refrigerant type.
7.5 Impeller Fan Replacement
The motorized impeller fan is a unitary assembly consisting of the
motor and impeller fan. If defective, the complete assembly must
be replaced.
1. Unplug the power cord.
2. Remove the cabinet access panel.
3. Remove the screw attaching the impeller fan support bracket
to the base.
4. Disconnect the impeller fan leads inside the electric box.
5. Remove fan/bracket assembly by removing 3 screws from
the bracket and inlet ring assembly.
6. Remove the defective impeller fan from the bracket and
replace with it with the new impeller fan.
7. Reassemble the new impeller fan by reversing the above
procedure. Note: There are two pins on the backside of the
cabinet that must align with the two holes in the impeller fan
support bracket.
7.6 Compressor/Capacitor Replacement
This compressor is equipped with a two terminal external
overload and a run capacitor, but no start capacitor or relay
(See Figure 4).